The present invention relates to mixing apparatus and pertains particularly to an improved rotary disc mixer.
Many manufacturing and other processes require the mixing of various liquids and materials in liquids. The traditional mixer is a rotating paddle arrangement mounted on a shaft and rotating about a vertical axis in a large vessel. In this arrangement a vertically mounted rotating shaft carries a plurality of paddles extending radially outward on arms disposed about the axis of the shaft. The rotating shaft moves the paddles through the liquid as the shaft rotates lifting the fluid from the bottom of the tank or vessel and pushing it to the top of the vessel. It does not pull the materials from the corners and crevices of the vessel. This typically results in the liquid and materials not being thoroughly mixed. Also these mixers dot not move the liquid and materials along the walls of the vessel.
The paddle system is satisfactory for many applications. However, particularly in the food and pharmaceutical industries, there are many delicate and fragile shear and impact sensitive materials that can be easily damaged with this type mixer. For this reason these materials cannot be satisfactorily mixed with these mixers and in this manner. The moving paddles can impact and bruise or otherwise cause damage to delicate and fragile materials.
Another material which cannot be satisfactorily mixed with the typical paddle mixer is highly viscous materials and materials having fibers and the like therein. These materials can build up on the paddles and can inhibit or resist turbulent flow necessary for thorough mixing.
Another class of materials which are not suitable for mixing with paddle mixers is highly abrasive materials. Such materials wear away the paddles at a rapid rate resulting in costly down time and repairs.
Accordingly there is a need for an improved mixing apparatus for mixing of delicate shear and impact sensitive materials and abrasive materials.
It is therefore desirable to have an improved mixing apparatus for mixing of delicate and other difficult to mix materials.